Due to the increasing spread of electric vehicles and the associated spread of charging stations, the electrical load on the electrical energy supply networks will increase. With an increasing load in the supply networks, however, the risk of network under-supply also increases. In the case of such under-supply, the electrical load is greater than the supply provided by the power stations (generators). In such a case, the load difference can only be covered from the kinetic energy of the rotating masses of the generators. This necessarily leads, however, to an under-frequency in the supply network, wherein the actual network frequency deviates from the reference value for the network.
Known measures for securing electricity supply consist of the detection of under-frequency and the use of under-frequency relays in transformer substations. If a frequency deviation of 1 Hz is detected, i.e. a frequency of 49 Hz in the network, then an immediate load shedding of 10 to 15% of the network load is put into effect by the opening of the under-frequency relays. This occurs regularly by load shedding at the high-voltage level by disconnecting the 110/10 Kv transformers. Load shedding in the medium-voltage transformers is also possible, however.
With the use of under-frequency relays, the entire transformer is separated from the network. This is increasingly problematic, because nowadays not only are consuming components connected to a transformer, but also generators. Due to the widespread use of wind generators and solar power systems, the situation may arise in some areas of the low-voltage, medium-voltage, and/or high-voltage sectors that, when a load shedding is desired, in fact a shedding of generation capacity also takes place. This, however, leads to network stabilisation not taking place. Instead, such a load shedding remains without effect. Intelligent solutions for load shedding are therefore necessary.
Against the background of the increasing load incurred by electric vehicles, the subject-matter was based on the object of providing charging stations with network stabilisation.